Hanger bracket and driving apparatus for plating barrels

ABSTRACT

The specification and drawings disclose a plating barrel assembly which comprises a barrel member mounted for rotation about its longitudinal axis. The barrel is supported from generally vertically extending hangers formed from metal reinforced plastic and are carried by a horizontally extending frame adapted to removably rest on the upper edge of the plating tank. Means are provided for rotating the barrel and the means include a shaft rotatably carried on the horizontal frame and connected through a gear train with a gear connected to an end of the drum. At least one end of the horizontal shaft extends outwardly of the frame for releasable engagement with a drive assembly. The drive assembly is mounted on one end of the plating tank and includes a first support frame mounted for vertical adjustment and including a horizontally extending portion and an inclined portion. A motor is adjustably mounted on the inclined portion and is drivingly connected with a gear reducer unit carried on the horizontal portion. The gear reducer is positioned with its output shaft extending horizontally and carrying a gear adapted to releasably engage a gear on the shaft member. The entire drum assembly has a low total height so that it can be easily lifted from the plating tank.

United States Patent Singleton [4 1 June 6,1972

[54] HANGER BRACKET AND DRIVING APPARATUS FOR PLATING BARRELS AlbertSingleton, 7360 Brookside Parkway, Middleburg Heights, Ohio 44l 3O [22]Filed: Nov. 20, 1970 [21] Appl.No.: 91,394

[72] Inventor:

Primary Examiner-John H. Mack Assistant ExaminerW. l. SolomonAttorney-Fay, Sharpe and Mulholland [5 7] ABSTRACT The specification anddrawings disclose a plating barrel assembly which comprises a barrelmember mounted for rotation about its longitudinal axis. The barrel issupported from generally vertically extending hangers formed from metalreinforced plastic and are carried by a horizontally extending frameadapted to removably rest on the upper edge of the plating tank. Meansare provided for rotating the barrel and the means include a shaftrotatably carried on the horizontal frame and connected through a geartrain with a gear con nected to an end of the drum. At least one end ofthe horizontal shaft extends outwardly of the frame for releasableengagement with a drive assembly. The drive assembly is mounted on oneend of the plating tank and includes a first support frame mounted forvertical adjustment and including a horizontally extending portion andan inclined portion. A motor is adjustably mounted on the inclinedportion and is drivingly connected with a gear reducer unit carried onthe horizontal portion. The gear reducer is positioned with its outputshaft extending horizontally and carrying a gear adapted to releasablyengage a gear on the shaft member. The entire drum assembly has a lowtotal height so that it can be easily lifted from the plating tank.

10 Claims, 8 Drawing Figures PATENTEDJUH 6 I972 SHEET 1 OF 3 INVENTOR.

ALBERT SINGLETON BY 4 6,, 5 :2 MW

ATTORNEYS PATENTEDJUH 6 I972 SHEET 2 OF 3 FIG. 2

FIG. 3

INVENTOR.

ALBERT SINGLETON BY 4m 5 $44M ATTORNEYS PATENTEDJUN 6 I972 SHEET 3 BF 3I: lllllllllliig INVENTOR.

ALBERT SINGLETON 4 a e a MW ATTORNEYS The present invention is directedtoward the metal finishing art and, more particularly, to an improvedplating barrel assembly for use in metal finishing operations.

The invention is especially suited for use as an electroplating barreland will be described with particular reference thereto; however, itshould be appreciated that apparatus of the type under consideration isused not only for plating but can also be used for cleaning,phosphating, and otherwise treating many types of parts. Hence, in thesubject specification and claims, the terms plating barrel is used forconvenience in referring to a barrel structure or apparatus forperforming this general type of operation and is not to be considered aslimited to only an apparatus for electroplating.

My US. Pat. No. 2,886,505, issued May 12, 1959 discloses a platingbarrel assembly of the general type under consideration. In usingplating barrels of this type, it is necessary to raise and lower thebarrel assembly from the tank of electrolyte at frequent intervalsduring operation. In a typical plating operation, there may be 30 to 100assemblies in use at any one time. Thus, it is important that the barrelassemblies be as compact as possible to minimize the vertical distancewhich the assemblies must be moved during the raising and loweringoperation.

Additionally, the power source and drive train for the barrel assemblyshould preferably be arranged so that the barrel assembly can be easilyseparated from the power source.

In addition to being compact and of relatively light weight, the barrelassembly must also be capable of operating in extremely corrosiveenvironments.

In accordance with one aspect of the invention, there is provided aplating barrel assembly which comprises a barrel member mounted forrotation about is longitudinal axis. The barrel is supported fromgenerally vertically extending hangers which are carried by ahorizontally extending frame adapted to rest on a plating tank. Meansare provided for rotating the barrel and the means include a shaftrotatably carried on the horizontal frame with a first gear fixed nearone end. A second gear is engaged with the first gear and rotatablycarried by a hanger member. A third gear is connected to the drum fordriving engagement with the second gear. At least one end of thehorizontal shaft extends outwardly of the first gear and is providedwith means for releasably engaging a drive means. Preferably, the drivemeans is mounted on one end of the plating tank and includes a firstsupport frame mounted for vertical adjustment and including ahorizontally extending portion and an inclined portion. A motor isadjustably mounted on the inclined portion and is drivingly connectedwith a gear reducer unit carried on the horizontal portion. The gearreducer is positioned with its output shaft extending horizontally andcarrying a gear adapted to releasably engage a gear on the shaft member.

Preferably, the hanger members comprise at least one plastic bar memberhaving a metal reinforcing rod sealed therein. The drum is carried on apair of hubs, one hub projecting from each hanger. Bearings mountedbetween the hubs and the drum comprise split rings, preferably formedfrom polypropylene filled with graphite, which minimize friction andgalling between the stationary hub and the rotating drum.

A further aspect of the invention concerns a method of reinforcingplastic with metal by a welding operation.

Accordingly, a primary object of the invention is the provision of theimproved barrel assembly and barrel mounting arrangement which allowsthe total assembly to have a short vertical height and to withstandrelatively rough usage in corrosive environments.

A still further object of the invention is the provision of a barrelassembly of the general type described which has a drive assembly thatis trouble-free and which automatically engages upon location of thebarrel over the plating tank.

A still further object of the invention is the provision of a barrelassembly of the general type described which has a drive assembly thatis trouble-free and which automatically engages upon location of thebarrel over the plating tank.

A further object is the provision of a bearing assembly for platingbarrels which can operate in extremely corrosive environments withoutgalling, seizing, or the like.

A still further object is the provision of a method of fonning metalreinforced polypropylene members.

These and other objects and advantages will become apparent from thefollowing description when read in conjunction with the accompanyingdrawings wherein:

FIG. 1 is a longitudinal cross-sectional view through a plating tank andbarrel assembly formed in accordance with the preferred embodiment ofthe invention;

FIG. 2 is an end view taken on line 2-2 of FIG. 1;

FIG. 3 is a view taken on line 3-3 of FIG. 2 showing the motor, gearreducer, and drive trail in detail;

FIG. 4 is a cross-sectional view taken on line 4-4 of FIG. 1 and showingthe gear train and barrel support bracket in detail;

FIG. 5 is a cross-sectional view taken on line 55 of FIG. 4;

FIG. 6 is a cross-sectional view taken on line 6-6 of FIG. 4 and showingthe mounting arrangement for the idler gear;

FIG. 7 is a cross-sectional view taken on line 7-7 of FIG. 4 and showingin detail the bearing and drum mounting assembly; and,

FIG. 8 is a cross-sectional view taken on line 8-8 of FIG. 4 and showingthe reinforcing arrangement utilized in the barrel hanger arms.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring moreparticularly to FIG. 1, the overall assembly is shown in some detail andcomprises an open topped tank 10 which functions to hold the electrolytesolution and supports the removable plating barrel assembly 12. Theparticular structural details of the tank 10 form no part of the presentinvention and could vary widely; however, in the preferred embodiment,the tank 10 is of generally rectangular shape having a flat bottom walland vertically extending side and end walls and is formed, for example,from metal and lined or covered with a relatively heavy corrosionresistant and non-electrically conductive material such as a suitablerubber or plastic material. Outwardly extending flanges 14 and 16 arejoined to the upper edges of the side and end walls.

The plating barrel assembly 12 is releasably and removably carried onthe outwardly extending flanges 14 and 16 at the upper end of tank 10 bya pair of straight cylindrical, low-resistance copper cathode rods 18and 20 of circular cross-section. As best shown in FIGS. 1 and 2, therods 18 and 20 are supported on the respective flanges by generallyrectangular mounting blocks 21 joined to the flanges by verticallyextending machine screws 22. Inthe embodiment under consideration, theblocks 21 are formed from polypropylene; however, it should beappreciated that other types of mounting blocks could be used. It willbe noted in FIG. 2 that the upper surfaces M of the blocks 21 areinclined downwardly toward the center of the tank. As will be describedmore fully hereafter, this arrangement of the blocks produces acentering action on the barrel assembly when it is positioned on thetank.

Of particular importance to the invention is the overall arrangement ofthe plating barrel assembly 12. The assembly 12 includes a support frame26 which extends across the upper end of the tank and carries the barrel28. The support frame 26 is comprised of a transversely extendingchannel member 29 which extends the length of the tank with its channellegs facing downwardly. Connected to the ends of the channel member 29are plates 30 [See FIGS. 1 and 3]. In the embodiment shown, the plates30 are welded to the channel ends and extend vertically and horizontallyof the channel. A pair of angle members 32 are releasably connected tothe plates 30 at each end of the channel by bolts 34. Electrical conduitor saddle blocks 36 of large cross-sectional area and low electricalresistance are connected to the lower faces of angles 32. Suitableinsulation is positioned between the angles 32 and the saddle blocks 36to prevent the flow of electricity therebetween. It will be noted thateach of the saddle blocks 36 has a generally V-shaped recess formed inits lower surface which is arranged to engage a corresponding cathoderod 18 or 20. Connected to the bars 36 are flexible electrodes orconduits 38 and 40 which will subsequently be described in more detail.

The barrel 28 is' supported from the channel member 29 by two pairs ofhangers 41, each having upwardly extending arms 42 and 44. The arms 42and 44 are adjustably joined to the channel by short anglemembers 46 and48 respectively [See FIG. 4]. Each of the angles 46 and 48 is welded toa lateral face of the channel 29 and has elongated bolt receiving slots47 and 49 formed therein. Suitable machine screws pass through the slotsinto engagement with the respective hanger arms. By releasing thescrews, the vertical position of the hangers 41 can be readily adjusted.

As best shown in FIGS. 1 and 4, the hangers extend vertically downwardfrom the channel 29 and support the drum within the electrolytesolution. The construction of the hangers is of particular importance tothe invention. As can be appreciated, because of the corrosive nature ofthe electrolyte or cleaning solutions used, the hangers, as well as theremaining elements of the drum assembly, must be capable of withstandinga particularly corrosive atmosphere. Further, the hangers must havesuitable strength to resist the forces exerted thereon during operationand use of the assembly. In the subject embodiment, the hanger'arms 42and 44 are formed from a corrosion resistant plastic such aspolypropylene with an internal reinforcing bar of steel or othersuitable metal. FIG. 8 is a cross-section through one of the-arms orbars 44 showing the internal reinforcing member 50 which is, in thisinstance, a flat steelbar. The construction of each of the hanger arms42 and 44 are identical and, accordingly, only one will be described indetail.

Referring again to FIG. 8, it will be seen that the arm 44 is formedfrom a rectangular, elongated section of polypropylene provided with alongitudinally extending slot 52 which is of a width sufficient toclosely receive the metal bar 50. The slot 52 extends into the main bodyof polypropylene a depth greater than the width of bar 50. Positionedover the outer edge of the bar and within the slot 52 is a strip 54 ofplastic or similar material having heat insulating each pair of thehanger arms and, in turn, supports a cylindrical hub member 60. The hubmembers 60 are removably connected to their respective block 58 bymachine screws 62 which extend inwardly through the blocks 58 intothreaded openings in the cylindrical hubs 60. It is obvious that the twoarms 42, 44 and the block 58 could be integral and could be formed bymerely cutting a slot in one end of a rectangular block of plastic toaccommodate the channel 29 et al, if

desired.

As noted in FIG. 1, electrode 40 extends through an opention andincludes the end walls 66 and 68 joined by flat,

properties. The strip 54 preferably extends throughout the length of thebar and is of a thickness sufficient to provide a groove inwardly fromthe outer edge of the slot 52. A second strip of plastic 56 is welded tothe main block over the strip 54. The welding is accomplished by aconventional plastic welding gun which extrudes a strip of heatedplastic into the groove for bonding with the side walls of the grooveand the insert 54. Insert 54 serves to prevent the metal reinforcing barfrom acting as a heat sink and conducting heat away from the heated weldstrip. Without strip 54, the weld bead 56 will deposit in the slotagainst the. bar 50 without bonding to either side wall. This layeredarrangement assures a good fluid tight weld joint between the strip 56and the main body of the block. Thus, the metal reinforcing strip istotally encased in the plastic and is not exposed to the corrosiveenvironment.

The purpose of the encapsulated steel bars 50 is to strengthen the arms42, 44 in shear, bending and torsion. The plastic is of sufficientstrength in tension to carry the load in the drum but without the steelbars the arms fail rather quickly due to the bending moments resultingfrom the drum rotation and the sway imparted by the tumbling partstherein.

In addition to reinforcing the hanger rods 41, the transverselyextending rods or bars 70 are also reinforced with steel strips 51(seeFIG. 4). I

The barrel is rotatably supported from the lower end of the hangers bythe assembly best shown in FIG. 7. It will be noted that a rectangularblock of polypropylene 58 is welded between the lower ends of the hangerarms 42, 44. Referring again to FIG. 1, one of the members 58 is carriedbetween rectangular side walls 69. The side walls are joined along theirmating longitudinal edges by suitable parallel reinforcing bars 70 (seeFIG. 4). Each of the side walls is preferably heavily perforated toallow free flow of the plating solution through the interior of thetank. Additionally, one of the side walls is removable and serves as anaccess opening. The access opening is held in position by suitableclamps or the like such as shown, for example, in my previouslymentioned U.S.'Pat. No. 2,886,505.

One important aspect of the invention is the bearing arrangement for thebarrels. As can be seen, the cylindrical hub members 60 extend intocentral openings formed in the end walls 66, 68. A sleeve bearing 71 ispositioned about the right hand hub 60 [as viewed in FIG. 1] while asimilar sleeve bearing 72 surrounds the left hand hub 60. The sleevebearing is a polypropylene bushing which is filled with graphite. Thisgreatly reduces friction and tends to eliminate freezing or gallingbetween the surfaces; however, it has been found that the use of thegraphite filled polypropylene alone does not completely eliminatefreezing and galling problems. For this reason, as best shown in FIGS. 4and 7, the bearings 71 and 72 are each provided with a longitudinal slot74. The bushing is maintained in position by a suitable pin 76 whichextends from the end plate 78 through the bearing 71. This causes thebearing 71 to rotate with the drum about the stationary hub 60. Shouldany seizing occur between the internal surface of the sleeve 71 and theouter surface of the hub 60, the groove or split 74 allows the bearing71 to expand radially thereby relieving the tension and allowing a quickslippage, thus minimizing any possibility of galling.

The drive assembly for the drum 28 includes a standard electric motorcarried at the right hand end of the tank 10. The motor is connectedthrough a three-step pulley 92, V-belt 94, and a second three-steppulley 96 with the input shaft of a right angle gear reducer 98. Themotor 90 and the gear reducer 98 are carried from an angle bracket orframe assembly 100 which is arranged for vertical adjustment to vary theelevation of the output shaft 102 of the gear reducer 98. The mountingbracket 100 includes a horizontal support plate 102 which is welded to avertically extending slide plate 104. An angle member 106 is connectedbetween the outer end of plate 102 and the lower end of slide plate 104.It will be noted that the gear reducer 98 is affixed to the surface ofplate 102 through the use of machine screws 108. In order to provide foradjustment of the mounting bracket in the vertical direction, it will benoted that the slide plate 104 is received within a guideway formed by apair of spaced members 110 [see FIG. 2] which have overlapping edgeportions that engage the slide plate at is opposite lateral edges. Theslide plate is suspended from the flange 16 of tank 10 by an elongatedstud bolt 112 that extends through openings in the support plate 102.Suitable nuts 114 allow the position of the angle bracket to be adjustedon the bolt 112. This arrangement permits the output shaft 102 to bepositioned precisely relative to the drive train to insure proper matingbetween the drive gears. Additionally, the motor mounting arrangement issuch that the belt 94 can be readily adjusted in tension. Also, the belt94 can be shifted between various steps of the pulleys to change thedrive speed of the drum 28.

Referring to FIG. 2, it will be seen that the motor 90 has its supportplate 116 slidably engaged with a pair of guideway forming members 118welded to the inclined plate 106. As mentioned, the motor mounting plate116 is freely slidable within the guideway forming members 118. To lockit in a desired position of adjustment, there is a thumb screw or the 7like 120 which passes through a threaded opening or nut member carriedon the plate 116. By tightening the nut or the screw member 120, the endof the screw engages the surface of the inclined bracket member 106.

An important feature of the invention is the construction of the drivetrain and its relationship to the frame and hanger assemblies. As shown,the drive train from the output shaft of the gear reducer 98 to thebarrel 28 includes a first pinion gear 130 which is formed from asuitable corrosion resistant plastic, preferably a thermoplastic ABSPolymer or polypropylene such as Seilon S3HT sold by Seiberling RubberCo. The gear 130 is connected to the shaft 102 by a set screw or othersuitable means. It will be noted that the gear 130 is positioned so asto be closely adjacent the end wall of the tank 10 and approximately atthe level of the flange 16. The flange 16 is cut out in the vicinity ofthe gear 103 to provide access to the pinion 130 by a driven pinion gear132.

In the aforementioned Singleton patent, it will be noted that thedriving gear projecting from the gear box is located wholly above thetop flange on the tank of fluid. With the improvement of the instantinvention, the driving gear 130 extending from the gear reducer 98 isalmost completely below the flange 16. This improvement allows theshortening of the distance between the barrel 28 and the frame 12 byabout 4 inches. While this may seem, relatively insignificant to theaverage man, to one of ordinary skill in the art, it will loom as asubstantial breakthrough in cost reduction. The costs in labor, time andpower involved in lifting a hundred loaded drums an extra 4 inches anhour, 24 hours a day is not inconsequential.

Note that the gear 132 is carried on the end of a horizontally extendingdrive shaft 134 which extends parallel to the channel 29. The shaft 134is carried in bearing blocks 136 which are formed from polypropylene orthe like and extend downwardly from the underface of channel 29. As bestshown in FIGS. 2 and 3, the bearing blocks 136 are supported fromchannel 29 by adjustable machine screws 138 which extend throughopenings in the channel. This allows the bearing blocks to be adjustedvertically with spacer washers and also permits them to be somewhatself-aligning.

Carried on the shaft intermediate the bearing blocks 136 is a piniongear 140. The gear 140 is drivingly engaged with an intermediate idlergear 142. As best shown in FIG. 4, the gear 142 is pinned to a stubshaft 144 carried from a support block 146. As shown in FIG. 6, thesupport block 146 is welded to the hanger arms 42, 44.

The gear 142 is engaged with a large diameter gear 148 connected to theend of the drum for producing rotation of the drum. As best shown inFIG. 1, the gear 148 is formed from plastic and is bolted to the endplate 78.

The arrangement described allows substantially the entire drive train tobe removed with the barrel assembly. Note that in FIG. 1 there is showna U-bolt 150 which is centrally positioned on the channel 29. In liftingthe barrel assembly, the barrel and the support frame are raisedupwardly causing the gear 132 to disengage gear 130. After the necessarysteps have been taken, such as filling the barrel and the like,replacement of the drum assembly is facilitated by the inclined surfacesof the blocks 21 [see FIG. 2]. The gears 132 and 130 are automaticallyre-engaged in their proper relationship upon replacement of the drumassembly in the tank 10.

Because of the torsional forces imparted to the idler gear 142 by thedriving pinion and the heavy loaded drum, special assembling techniquesare employed. The stub shaft 144 includes a hole 152 threadedtranversely of its axis. A screw 154 projects through an aperture in thegullet of one of the gear teeth and into the hole. This locks the shahand gear together with the gear substantially flush with the side ofsupport block 146. Thus, torsional forces imparted to the gear 142 willimmediately be transferred to the stronger block 146 due to theface-to-face contact, rather than tending to twist the gear out ofalignment. The driving gear 140 is similarly attached to shaft 134.

Friction between the polypropylene block and gear is at a minimum andthe shaft 144 is joumalled in a Teflon bushing 156. Because of thecorrosive nature of the environment, it is preferred that the screws forlocking the gears 140, 142 to the shafts 134, 144, respectively, be ofstainless steel, titanium, Carpenter No. 2OCB or of suitable plastic.

The invention has been described in great detail sufiicient to enableone of ordinary skill in the metal treating art to make and use thesame. Obviously, modifications and alterations of the preferredembodiment will occur upon a reading and understanding of thespecification and it is my intention to include all such modificationsand alterations as part of my invention insofar as they come within thescope of the appended claims.

What is claimed is:

1. A plating barrel assembly for finishing parts adapted for use inelectroplating in combination with electrodes compris mg:

a barrel member mounted for rotation about is longitudinal axis;

hanger members supporting said barrel and extending downwardly from ahorizontally extending frame adapted to rest on a plating tank;

means for rotating said barrel comprising a shaft member rotatablysupported from said frame and having a first gear member carriedthereon;

a second gear carried from one of said hangers and engaging said firstgear, said second gear including a flat side in constant direct contactwith a flat surface on one of said hangers of a size at least equal tothe size of the gear, a third gear connected to said drum and engagingsaid second gear;

said shaft having at least one end extending outwardly from said firstgear for engagement with drive means; and

means on the ends of said frame for locating said assembly on a platingtank.

2. The apparatus of claim 1 wherein said hanger members comprise atleast one plastic bar member having a metal reinforcing rod sealedtherein.

3. The apparatus of claim 1 wherein all of said gears are formed fromplastic.

4. The apparatus of claim 1 including a plating tank having a driveassembly carried on one end thereof;

said drive assembly including a first support frame mounted for verticaladjustment and including a horizontally extending portion and aninclined portion;

a motor adjustably mounted on said inclined portion and drivinglyconnected with a gear reducer unit carried on said horizontal portion,said gear reducer having a horizontally extending output shaft providedwith a gear adapted to engage a gear on the shaft which carries saidfirst gear.

5. The apparatus of claim 4 wherein the means for adjusting the driveassembly support plate comprise a threaded member extending downwardlyfrom a peripheral flange on said tank.

6. The apparatus of claim 4 wherein said motor is adapted for adjustingmovement along said inclined portion.

7. The apparatus of claim 4 including a flange extending about the upperend of said tank and wherein the gear on said gear reducer output shaftextends upwardly through an opening formed in said flange.

8. The apparatus of claim 4 including cooperating inclined surfaces onsaid frame and said tank for aligning said drum assembly with said tank.

9. In the combination of a foraminous hollow barrel enclosing metallicarticles to be treated by fluid which penetrates said barrel fromwithout,

hanger brackets for supporting said barrel for rotation about its axisin a substantially horizontal plane,

a support frame for supporting said brackets,

gear and motor means for rotating said drum, and

electrode means for passing electric current through said fluid, theimprovement comprising:

hubs extending through apertures in each end of said barrel along itsaxis, said hubs being rigidly fixed to said brackets,

locked for rotation with said barrel while said hub remains stationary.

1. A plating barrel assembly for finishing parts adapted for use inelectroplating in combination with electrodes comprising: a barrelmember mounted for rotation about is longitudinal axis; hanger memberssupporting said barrel and extending downwardly from a horizontallyextending frame adapted to rest on a plating tank; means for rotatingsaid barrel comprising a shaft member rotatably supported from saidframe and having a first gear member carried thereon; a second gearcarried from one of said hangers and engaging said first gear, saidsecond gear including a flat side in constant direct contact with a flatsurface on one of said hangers of a size at least equal to the size ofthe gear, a third gear connected to said drum and engaging said secondgear; said shaft having at least one end extending outwardly from saidfirst gear for engagement with drive means; and means on the ends ofsaid frame for locating said assembly on a plating tank.
 2. Theapparatus of claim 1 wherein said hanger members comprise at least oneplastic bar member having a metal reinforcing rod sealed therein.
 3. Theapparatus of claim 1 wherein all of said gears are formed from plastic.4. The apparatus of claim 1 including a plating tank having a driveassembly carried on one end thereof; said drive assembly including afirst support frame mounted for vertical adjustment and including ahorizontally extending portion and an inclined portion; a motoradjustably mounted on said inclined portion and drivingly connected witha gear reducer unit carried on said horizontal portion, said gearreducer having a horizontally extending output shaft provided with agear adapted to engage a gear on the shaft which carries said firstgear.
 5. The apparatus of claim 4 wherein the means for adjusting thedrive assembly support plate comprise a threaded member extendingdownwardly from a peripheral flange on said tank.
 6. The apparatus ofclaim 4 wherein said motor is adapted for adjusting movement along saidinclined portion.
 7. The apparatus of claim 4 including a flangeextending about the upper end of said tank and wherein the gear on saidgear reducer output shaft extends upwardly through an opening formed insaid flange.
 8. The apparatus of claim 4 including cooperating inclinedsurfaces on said frame and said tank for aligning said drum assemblywith said tank.
 9. In the combination of a foraminous hollow barrelenclosing metallic articles to be treated by fluid which penetrates saidbarrel from without, hanger brackets for supporting said barrel forrotation about its axis in a substantially horizontal plane, a supportframe for supporting said brackets, gear and motor means for rotatingsaid drum, and electrode means for passing electric current through saidfluid, the improvement comprising: hubs extending through apertures ineach end of said barrel along its axis, said hubs being rigidly fixed tosaid brackets, openings through said hubs, said electrode meansextending through said openings, one of said openings being inclineddownwardly from outside the barrel toward the inside, a cylindricalbearing disposed between each hub and the barrel to support the barrelin sliding rotary movement, said bearing being formed from a mixture ofpolypropylene and graphite, saId bearing including a longitudinal slitextending for its full length to allow the bearing to expand radially torelieve tension and minimize galling during rotary movement of saidbarrel.
 10. The combination of claim 9 wherein the bearing is locked forrotation with said barrel while said hub remains stationary.